Low cut-off ultrafiltration membranes
a technology of ultrafiltration membranes and hollow fibers, which is applied in the direction of membranes, filtration separation, separation processes, etc., can solve the problems of increasing difficulty in achieving the goal, and achieve the effects of reducing the molecular weight, enhancing the hydraulic permeability, and high pressure stability
- Summary
- Abstract
- Description
- Claims
- Application Information
AI Technical Summary
Benefits of technology
Problems solved by technology
Method used
Image
Examples
example 1
[0092]A polymer solution was prepared by dissolving polyethersulfone (Ultrason® 6020, BASF SE) and polyvinylpyrrolidone (K30 and K85, BASF SE) and distilled water in N-methylpyrrolidone (NMP). The weight fraction of the different components in the polymer spinning solution was: PES:PVP K85:PVP K30:H2O:NMP=14:2:5:3:76. The viscosity of the polymer solution was 6,000 mPa·s.
[0093]The sequence of adding the polymer material to the solvent, the temperature and the stirring time are important. A clear solution without any turbidity and bubbles is subsequently needed for a uniform morphology and performance of the membrane. Particles or bubbles in the polymer solution disturb the coagulation process and can lead to defects in membrane structure.
[0094]To prepare the solution, NMP and water were first filled into a 30 L container with finger-paddle agitator. The PVP was added to the NMP and stirred at 60° C. until a homogeneous clear solution was obtained. Finally, the polyethersulfone was a...
example 2
[0104]Example 1 was repeated using a center fluid containing 90 wt % water and 10 wt % NMP.
[0105]The hollow fiber membrane had an inner diameter of 293 μm and a wall thickness of 60 μm. The dry hollow fiber membrane had a fully asymmetric membrane structure. The active separation layer of the membrane was at the inner side.
[0106]FIG. 2 shows a scanning electron micrograph of the cross-section of the hollow fiber membrane [Magnification 2,000; the white bar indicates 20 μm] and the inner surface [Magnification 60,000; the white bar indicates 500 nm]. The wall has an asymmetric structure and the inner surface shows a very homogeneous pore size distribution.
[0107]The sieving coefficient for inulin was determined to be 9% (mean value of t=0 and t=15 min) and hydraulic permeability was 2.9×10−4 cm3 / cm2×s×bar (n=2). The increase of the water concentration in the center fluid (in comparison to Example 1) resulted in a denser inner surface and a reduction of the hydraulic permeability and t...
example 3
[0109]A polymer solution was prepared by dissolving polyethersulfone (Ultrason® 6020, BASF SE) and polyvinylpyrrolidone (K30 and K85, BASF SE) and distilled water in N-methylpyrrolidone (NMP). The weight fraction of the different components in the polymer spinning solution was: PES:PVP K85:PVP K30:H2O:NMP=14:2.5:6:6:68.5. The viscosity of the polymer solution was 25,780 mPa·s.
[0110]A membrane was formed by heating the polymer solution to 35° C. and passing the solution as well as the center fluid through a spinning die. A center fluid containing 90 wt % water and 10 wt % NMP was used. The diameter of the inner bore was 180 μm and the diameter of the outer orifice was 700 μm. The temperature of the die was 35° C., the temperature of the spinning shaft was 32° C. The hollow fiber membrane was formed at a spinning speed of 12.5 m / min. The liquid capillary leaving the die was passed into a water bath having a temperature of 25° C. The distance between the die and the precipitation bath ...
PUM
| Property | Measurement | Unit |
|---|---|---|
| Temperature | aaaaa | aaaaa |
| Temperature | aaaaa | aaaaa |
| Temperature | aaaaa | aaaaa |
Abstract
Description
Claims
Application Information
Login to View More